Liquid crystal display

ABSTRACT

A liquid crystal display includes a first substrate, a second substrate disposed opposite to the first substrate; a pixel electrode disposed on the first substrate; a common electrode disposed on the second substrate; and a liquid crystal layer disposed between the first substrate and the second substrate, where a first cutout having a cross shape is defined in the common electrode, a second cutout is defined in the pixel electrode to be adjacent to and along an edge of the pixel electrode, and the pixel electrode has a step structure, a boundary line of which is in a rhombus shape.

This application claims priority to Korean Patent Application No.10-2013-0101129, filed on Aug. 26, 2013, and all the benefits accruingtherefrom under 35 U.S.C. §119, the contents of which are incorporatedby reference herein in its entirety.

BACKGROUND

(a) Field

The invention relates to a liquid crystal display (“LCD”), and moreparticularly, to an LCD with improved aperture ratio and improved liquidcrystal controlling power.

(b) Description of the Related Art

A liquid crystal display (“LCD”), which is one of the most widely usedtypes of flat panel display, typically includes two display panels onwhich field generating electrodes, such as a pixel electrode and acommon electrode, are provided, and a liquid crystal layer disposedtherebetween. The LCD generates an electric field on the liquid crystallayer by applying voltage to the electric field generating electrode,determines a direction of liquid crystal molecules of the liquid crystallayer through the generated electric field, and displays an image bycontrolling polarization of incident light.

Among LCDs, in a vertically aligned (“VA”) mode LCD, in which liquidcrystal molecules are aligned to enable a longitudinal axes thereof tobe vertical with respect to a display panel in a state in which anelectric field is not generated therein, a method of forming a cutoutsuch as a micro slit on an electric field generating electrode is usedto secure a wide viewing angle. In such a VA mode LCD, a cutout and aprotrusion may determine a tilt direction in which liquid crystalmolecules are tilted. Accordingly, a viewing angle may be improved byappropriately disposing the cutout and the protrusion and therebydistributing tilting directions of the liquid crystal molecules into aplurality of directions.

In such a VA mode LCD, when a plurality of branch electrodes areprovided by forming a micro slit on a pixel electrode, an aperture ratioof the LCD may decrease.

SUMMARY

Exemplary embodiments of the invention provide a liquid crystal display(“LCD”) with improved aperture ratio and having a wide viewing angle anda quick response speed.

Exemplary embodiments of the invention also provide an LCD with improvedliquid crystal controlling power.

An exemplary embodiment of the invention provides an LCD including: afirst substrate; a second substrate disposed opposite to the firstsubstrate; a pixel electrode disposed on the first substrate; a commonelectrode disposed on the second substrate; and a liquid crystal layerdisposed between the first substrate and the second substrate, where afirst cutout having a cross shape is defined in the common electrode, asecond cutout is defined in the pixel electrode to be adjacent to andalong an edge of the pixel electrode, the pixel electrode has a stepstructure, and a boundary line of the step structure has a rhombusshape.

In an exemplary embodiment, the first cutout may overlap two diagonallines in the rhombus shape of the boundary line of the step structure.

In an exemplary embodiment, a vertex of the rhombus shape of theboundary line of the step structure may be chamfered.

In an exemplary embodiment, a side surface of the pixel electrode at theboundary line of the step structure may form an angle in a range ofabout 35 degrees to about 65 degrees with the first substrate.

In an exemplary embodiment, the step structure may have a heightdifference in a range of about 500 angstroms (Å) to about 2,200 Å.

In an exemplary embodiment, an angle between the boundary line of thestep structure and the first cutout may be in a range of about 40degrees to about 50 degrees.

In an exemplary embodiment, the LCD may further include a passivationlayer disposed below the pixel electrode, where an opening in therhombus shape is defined in the passivation layer.

In an exemplary embodiment, the boundary line of the step structure maymatch an outline of the opening in the passivation layer.

In an exemplary embodiment, the first cutout may overlap two diagonallines in the rhombus shape of the opening in the passivation layer.

In an exemplary embodiment, a vertex of the rhombus shape of the openingin the passivation layer may be chamfered.

In an exemplary embodiment, a side surface of the passivation layerwhich defines the opening may have a tapered angle in a range of about35 degrees to about 65 degrees.

In an exemplary embodiment, a thickness of the passivation layer may bein a range of about 500 Å to about 2,200 Å.

In an exemplary embodiment, an angle between an outline of the openingand the first cutout may be in a range of about 40 degrees to about 50degrees.

In an exemplary embodiment, the LCD may further include an organicmaterial layer disposed below the passivation layer, where the organicmaterial layer may include a groove portion in the rhombus shape.

In an exemplary embodiment, the organic material layer may include atleast one of a color filter, an organic insulating layer and anovercoat.

In an exemplary embodiment, the boundary line of the step structure maymatch an outline of the groove portion.

In an exemplary embodiment, the first cutout may overlap two diagonallines in the rhombus shape of the groove portion.

In an exemplary embodiment, a side surface of the groove portion mayform an angle in a range of about 35 degrees to about 65 degrees withrespect to a bottom surface of the groove portion.

In an exemplary embodiment, the LCD may further include: a firstalignment layer disposed on the first substrate and the pixel electrode;and a second alignment layer disposed on the second substrate and thecommon electrode, where the first alignment layer and the secondalignment layer may be vertical alignment layers, the liquid crystallayer may include liquid crystal molecules and reactive mesogen, and theliquid crystal molecules may be aligned to have a pretilt angle.

In an exemplary embodiment, the LCD may further include: a firstalignment layer disposed on the first substrate and the pixel electrode;and a second alignment layer disposed on the second substrate and thecommon electrode, where the first alignment layer and the secondalignment layer may include an alignment material and reactive mesogen,and the first alignment layer and the second alignment layer may alignliquid crystal molecules in the liquid crystal layer to have a pretiltangle.

In exemplary embodiments, the LCD may have an expanded viewing angle,improved response speed and increased aperture ratio by providing afirst cutout having a cross shape in the common electrode and a secondcutout in the pixel electrode to be adjacent to an edge of the pixelelectrode.

In such embodiments, the pixel electrode has a step structure having aboundary line in a rhombus shape, such that a liquid crystal controllingpower is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the invention will become more apparentby describing in detail exemplary embodiments thereof with reference tothe accompanying drawings, in which:

FIG. 1 is an equivalent circuit diagram illustrating a pixel of anexemplary embodiment of a display device, according to the invention;

FIG. 2 is a layout view illustrating a pixel of an exemplary embodimentof a display device, according to the invention;

FIG. 3 is a cross-sectional view taken along line III-III of a thedisplay device shown in FIG. 2, where the display device is an liquidcrystal display (“LCD”);

FIG. 4 is a top plan view illustrating a unit region of a fieldgenerating electrode of an exemplary embodiment of an LCD, according tothe invention;

FIG. 5 is a view illustrating a process of enabling liquid crystalmolecules to have a pretilt angle using a prepolymer polymerized bylight such as ultraviolet rays;

FIG. 6 is a cross-sectional view illustrating a pixel of an alternativeexemplary embodiment of an LCD, according to the invention;

FIG. 7 is a graph illustrating a stain visibility level based on a stepstructure of a pixel electrode in an exemplary embodiment of an LCD,according to the invention;

FIG. 8 is a graph illustrating a stain visibility level based on atapered angle of a second passivation layer in an exemplary embodimentof an LCD, according to the invention;

FIG. 9 is a graph illustrating a transmittance based on a step structureof a pixel electrode in an exemplary embodiment of an LCD, according tothe invention;

FIG. 10 is a top plan view illustrating a unit region of a fieldgenerating electrode of an alternative exemplary embodiment of an LCD,according to the invention; and

FIG. 11 and FIG. 12 are top plan views illustrating a unit region of afield generating electrode of another alternative exemplary embodimentof an LCD, according to the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Hereinafter, a pixel of an exemplary embodiment of a display device,according to the invention will be briefly described below withreference to FIGS. 1 and 2.

FIG. 1 is an equivalent circuit diagram illustrating a pixel of anexemplary embodiment of a display device, according to the invention,and FIG. 2 is a plan view illustrating a pixel of an exemplaryembodiment of a display device, according to the invention.

An exemplary embodiment of the display device includes signal lines suchas a gate line 121, a storage electrode line 131, a decompression gateline 123 and a data line 171.

In such an embodiment, the display device further includes a firstswitching element (Qh), a second switching element (Ql), a thirdswitching element (Qc), a first liquid crystal capacitor (Clch), asecond liquid crystal capacitor (Clcl), a first storage capacitor(Csth), a second storage capacitor (Cstl) and a decompression capacitor(Cstd), which are connected to the signal lines. Hereinafter, the firstswitching element (Qh) may be referred to as a first thin filmtransistor (Qh), the second switching element (Ql) may be referred to asa second thin film transistor (Ql), and the third switching element (Qc)may be referred to as a third thin film transistor (Qc).

Each of the first and second switching elements (Qh and Ql) areconnected to the gate line 121 and the data line 171. The thirdswitching element (Qc) is connected to the decompression gate line 123.

The first and second switching elements (Qh and Ql) are three-terminalelements, e.g., thin film transistors, disposed on a first substrate 110(shown in FIG. 3). Control terminals of the first and second switchingelements (Qh and Ql) are connected to the gate line 121, input terminalsof the first and second switching elements (Qh and Ql) are connected tothe data line 171, and output terminals of the first and secondswitching elements (Qh and Ql) are connected to the first and secondliquid crystal capacitor (Clch and Clcl) and the first and secondstorage capacitor (Csth and Cstl), respectively.

The third switching element (Qc) is also a three-terminal element, e.g.,a thin film transistor, disposed on the first substrate 110. A controlterminal of the third switching element (Qc) is connected to thedecompression gate line 123, an input terminal of the third switchingelement (Qc) is connected to the decompression capacitor (Cstd), and anoutput terminal of the third switching element (Qc) is connected to thesecond liquid crystal capacitor (Clcl).

The first and second liquid crystal capacitors (Clch and Clcl) areconfigured by overlapping portions of a common electrode 270 and thefirst and second sub-pixel electrodes 191 h and 191 l that are connectedto the first and second switching elements (Qh and Ql), respectively.The first and second storage capacitors (Csth and Cstl) are configuredby overlapping portions of the first and second sub-pixel electrodes 191h and 191 l, and the storage electrode line 131.

The decompression capacitor (Cstd) is connected to the input terminal ofthe third switching element (Qc) and the storage electrode line 131, andconfigured by overlapping portions of the storage electrode line 131 andthe input terminal of the third switching element (Qc) with an insulatordisposed between the overlapping portions.

Next, an exemplary embodiment of a driving method of the display deviceillustrated in FIGS. 1 and 2 will be described.

When a gate-on signal is applied to the gate line 121, the firstswitching element (Qh) and the second switching element (Ql) connectedthereto are turned on. Accordingly, data voltage applied to the dataline 171 is applied to the first sub-pixel electrode 191 h and thesecond sub-pixel electrode 191 l through the turned-on first switchingelement (Qh) and second switching element (Ql). Here, substantially thesame magnitude of data voltage is applied to the first sub-pixelelectrode 191 h and the second sub-pixel electrode 191 l. Accordingly,substantially the same voltage is charged to the first and second liquidcrystal capacitors (Clch and Clcl).

Next, when a gate-off signal is applied to the gate line 121 and agate-on signal is applied to the decompression gate line 123, the firstswitching element (Qh) and the second switching element (Ql) are turnedoff and the third switching element (Qc) is turned on. Next, chargesmove from the second sub-pixel electrode 191 l to the decompressioncapacitor (Cstd) through the turned-on third switching element (Qc).Next, charging voltage of the second liquid crystal capacitor (Clcl)decreases and the decompression capacitor (Cstd) is charged. Thecharging voltage of the second liquid crystal capacitor (Clcl) decreasesby capacitance of the decompression capacitor (Cstd) and thus, thecharging voltage of the second liquid crystal capacitor (Clcl) decreasesto be lower than the charging voltage of the first liquid crystalcapacitor (Clch).

Here, charging voltages of two liquid crystal capacitors (Clch and Clcl)in a pixel indicates a different gamma curve, and a gamma curve of apixel voltage becomes a curve in which the charging voltages of the twoliquid crystal capacitors (Clch and Clcl) are combined. In such anembodiment, a combined gamma curve from a front view matches a referencegamma curve of the front view, which may be predetermined as an optimalgamma curve for the front view, and a combined gamma curve from a sideview may be substantially closest to the reference gamma curve of thefront view. As described above, in such an embodiment, a side visibilityis substantially improved by controlling charging voltages of the twoliquid crystal capacitors (Clch and Clcl) based on image data.

Hereinafter, an exemplary embodiment of a liquid crystal display(“LCD”), according to the invention, will be further described withreference to FIGS. 2 and 3.

FIG. 3 is a cross-sectional view taken along line III-III of the displaydevice shown in FIG. 2, where the display device is an LCD.

An exemplary embodiment of the LCD includes a lower panel 100 and anupper panel 200 disposed to face each other, and a liquid crystal layer3 disposed between the lower panel 100 and the upper panel 200.

Hereinafter, the lower panel 100 will be described in greater detail.

The gate line 121, the decompression gate line 123 and the storageelectrode line 131 are disposed on the first substrate 110.

The gate line 121 and the decompression gate line 123 extendsubstantially in a horizontal direction and transfer a gate signal. Afirst gate electrode 124 h and a second gate electrode 124 l areprotruded from the gate line 121, and a third gate electrode 124 c isprotruded from the decompression gate line 123. The first gate electrode124 h and the second gate electrode 124 l may be connected to each otherto thereby form a single protruding portion. In such an embodiment, theprotruding shape of the first, second and third gate electrodes 124 h,124 l and 124 c may be variously modified.

The storage electrode line 131 extends substantially in the horizontaldirection and transfers determined voltage such as common voltage. Astorage electrode 133 and a protruding portion 134 are protruded fromthe storage electrode line 131. The storage electrode 133 may surround apixel electrode 191. The protruding portion 134 may be protruded towardthe gate line 121.

A gate insulating layer 140 is disposed on the gate line 121, the firstto third gate electrodes 124 h, 124 l and 124 c, the storage electrodeline 131, the storage electrode 133, and the protruding portion 134. Thegate insulating layer 140 may include an inorganic insulating materialsuch as silicon nitride (SiNx) and silicon oxide (SiOx), for example.Also, the gate insulating layer 140 may have a single-layer structure ora multi-layer structure.

A first semiconductor 154 h, a second semiconductor 154 l and a thirdsemiconductor 154 c are disposed on the gate insulating layer 140. Thefirst semiconductor 154 h may be in a region corresponding to the firstgate electrode 124 h, the second semiconductor 154 l may be in a regioncorresponding to the second gate electrode 124 l, and the thirdsemiconductor 154 c may be in a region corresponding to the third gateelectrode 124 c.

The first to third semiconductors 154 h, 154 l and 154 c may includeamorphous silicon, polycrystalline silicon or metal oxide, for example.

An ohmic contact (not shown) may be further disposed on each of thefirst to third semiconductors 154 h, 154 l and 154 c.

A data conductor including the data line 171, a first source electrode173 h, a second source electrode 173 l, a third source electrode 173 c,a first drain electrode 175 h, a second drain electrode 175 l and athird drain electrode 175 c is disposed on the first to thirdsemiconductors 154 h, 154 l and 154 c.

In an exemplary embodiment, the first to third semiconductors 154 h, 154l and 154 c may be disposed on the first to third gate electrodes 124 h,124 l and 124 c, respectively, and may be disposed below the data line171. In an exemplary embodiment, the second semiconductor 154 l and thethird semiconductor 154 c may be connected to each other. However, theinvention is not limited thereto. In an alternative exemplaryembodiment, the first to third semiconductors 154 h, 154 l and 154 c maybe disposed only on the first to third gate electrodes 124 h, 124 l and124 c, and the second semiconductor 154 l and the third semiconductor154 c may be spaced apart from each other.

The data line 171 transfers a data signal and extends substantially in avertical direction to cross the gate line 121 and the decompression gateline 123.

The first source electrode 173 h is protruded from the data line 171 anddisposed on the first gate electrode 124 h, and the second sourceelectrode 173 l is disposed on the second gate electrode 124 l. Thefirst source electrode 173 h and the second source electrode 173 l areconnected to each other and are applied with a same data signal from thedata line 171.

Each of the first drain electrode 175 h and the second drain electrode175 l include a wide end portion and a bar-shaped end portion. Thebar-shaped end portions of the first drain electrode 175 h and thesecond drain electrode 175 l are partially surrounded by the firstsource electrode 173 h and the second source electrode 173 l. The wideend portion of the second drain electrode 175 l further extends and isconnected to the third drain electrode 175 c bent in a U-like shape.

The third source electrode 173 c is disposed on the protruding portion134 and the third gate electrode 124 c. An end of the third sourceelectrode 173 c is disposed to face the third drain electrode 175 c onthe third gate electrode 124 c.

The first, second and third gate electrodes 124 h, 124 l and 124 c, thefirst, second and third source electrodes 173 h, 173 l and 173 c, andthe first, second and third drain electrodes 175 h, 175 l and 175 ccollectively define first, second and third thin film transistors (Qh,Ql, and Qc) together with the first, second and third semiconductors 154h, 154 l and 154 c, respectively. A channel of each of the first, secondand third thin film transistors (Qh, Ql, and Qc) is formed on acorresponding semiconductor of the first to third semiconductors 154 h,154 l, and 154 c between a corresponding source electrode of the firstto third source electrodes 173 h, 173 l and 173 c and a correspondingdrain electrode of the first to third drain electrodes 175 h, 175 l and175 c.

A first passivation layer 180 p is disposed on the data line 171, thefirst to third source electrodes 173 h, 173 l and 173 c, the first tothird drain electrodes 175 h, 175 l and 175 c, and an exposed portion ofthe first to third semiconductors 154 h, 154 l and 154 c between thefirst to third source electrodes 173 h, 173 l and 173 c, and the firstto third drain electrodes 175 h, 175 l and 175 c, respectively. Thefirst passivation layer 180 p may include an inorganic insulatingmaterial such as silicon nitride (SiNx) and silicon oxide (SiOx), forexample.

A color filter 230 is disposed on the first passivation layer 180 p. Thecolor filter 230 is positioned on substantially an entire region of thefirst substrate 110 excluding regions at which the first thin filmtransistor (Qh), the second thin film transistor (Ql) and the third thinfilm transistor (Qc) are positioned. In an alternative exemplaryembodiment, the color filter 230 may extend to be elongated in avertical direction along the neighboring data line 171. Each colorfilter 230 may display one of primary colors, such as three primarycolors of red, green and blue, but not being limited thereto. In analternative exemplary embodiment, the color filter 230 may display cyan,magenta, yellow and white-based color.

A light blocking member 220 is disposed on a region, in which the colorfilter 230 is not positioned, and on a portion of the color filter 230.The light blocking member 220 is also referred to as a black matrix andblocks a light leakage. The light blocking member 220 extends along thegate line 121 and the decompression gate line 123 and may be verticallyarranged. In such an embodiment, the light blocking member 220 mayinclude a horizontal light blocking member configured to cover a regionin which the first thin film transistor (Qh), the second thin filmtransistor (Ql) and the third thin film transistor (Qc) are positioned,and a vertical light blocking member that extends along the data line171. A height of a portion of the light blocking member 220 may be lowerthan a height of the color filter 230.

A second insulating layer 180 q is disposed on the color filter 230 andthe light blocking member 220. The second insulating layer 180 q mayinclude an inorganic insulating material such as SiNx and SiOx, forexample. The second passivation layer 180 q effectively prevents thecolor filter 230 and the light blocking member 220 from being gaped froma layer therebelow, substantially reduces contamination of the liquidcrystal layer 3 by an organic material such as a solvent inflowing fromthe color filter 230, and thereby effectively prevents a defect such asan afterimage that may occur when displaying an image on a screen of theLCD.

A first contact hole 185 h and a second contact hole 185 l configured toexpose the wide end portion of the first drain electrode 175 h and thewide end portion of the second drain electrode 175 l, respectively, aredefined, e.g., formed, through the first passivation layer 180 p, thelight blocking member 220 and the second passivation layer 180 q.

Also, openings 187 a and 187 b in a rhombus shape are defined on thesecond passivation layer 180 q. As illustrated in FIG. 2, a vertex ofthe rhombus shape of the openings 187 a and 187 b may be chamfered. Aside surface of the second passivation layer 180 q exposed by theopenings 187 a and 187 b may be tapered at an angle of in a range ofabout 35 degrees to about 65 degrees.

A thickness of the second passivation layer 180 q may be in a range ofabout 500 angstroms (Å) to about 2,200 Å. Accordingly, a stepcorresponding to the thickness of the second passivation layer 180 q ina range of about 500 Å to about 2,200 Å may be formed between a portionof the second passivation layer 180 q in which the openings 187 a and187 b are defined and a portion of the second passivation layer 180 q inwhich the openings 187 a and 187 b are not defined.

The pixel electrode 191 is disposed on the second passivation layer 180q. Second cutouts 91 a and 91 b adjacent to and along at least a portionof an edge of the pixel electrode 191 is defined in the pixel electrode191. In such an embodiment, where the second cutouts 91 a and 91 b aredefined in the pixel electrode 191 along the edge of the pixel electrode191, a fringe field is generated even on an edge of a pixel region,alignment of liquid crystal molecules may be effectively adjusted in apredetermined direction. The pixel electrode 191 may include atransparent conductive material such as indium tin oxide (“ITO”) andindium zinc oxide (“IZO”), for example.

The pixel electrode 191 has a step structure at a boundary line of therhombus shape of the openings 187 a and 187 b. The boundary line of thestep structure of the pixel electrode 191 matches outlines of theopenings 187 a and 187 b of the second passivation layer 180 q. That is,the pixel electrode 191 is disposed on the second passivation layer 180q and the openings 187 a and 187 b and thus, has the step structure atthe outlines of the openings 187 a and 187 b. In such an embodiment, thestep structure of the pixel electrode 191 may include an upper portiondisposed on the second passivation layer 180 q and a lower portiondisposed in a same layer as the second passivation layer 180 q on thecolor filter 230. The boundary line of the step structure is a boundaryline between the lower and upper portions of the step structure.

The boundary line of the step structure has substantially the same shapeas the outlines of the openings 187 a and 187 b. Accordingly, a vertexof the rhombus shape corresponding to the boundary line of the stepstructure may be chamfered.

The boundary line of the step structure of the pixel electrode 191 has aboundary structure corresponding to the tapered angle of the side of thesecond passivation layer 180 q such that the boundary structure forms anangle in a range of about 35 degrees to about 65 degrees with the firstsubstrate 110.

The step structure may have a step difference in a range of about 500 Åto about 2,200 Å, which corresponds to the thickness of the secondpassivation layer 180 q.

The pixel electrode 191 includes the first sub-pixel electrode 191 h andthe second sub-pixel electrode 191 l that are separate from each otherbased on the gate line 121 and the decompression gate line 123, aredisposed in upper and lower portion of a pixel region PX based on thegate line 121 and the decompression gate line 123, and thereby neighboreach other in the vertical direction.

The first sub-pixel electrode 191 h and the second sub-pixel electrode191 l are connected to the first drain electrode 175 h and the seconddrain electrode 175 l through the first contact hole 185 h and thesecond contact hole 185 l, respectively. Accordingly, when the firstthin film transistor (Qh) and the second thin film transistor (Ql) arein a turn-on state, the first sub-pixel electrode 191 h and the secondsub-pixel electrode 191 l are applied with data voltage from the firstdrain electrode 175 h and the second drain electrode 175 l,respectively.

A first alignment layer 11 is disposed on the pixel electrode 191 andthe second passivation layer 180 q. The first alignment layer 11 may bea vertical alignment layer, and may be an alignment layer, which isphoto-aligned using a photo-polymerization material.

Hereinafter, the upper panel 200 will be described in greater detail.

The common electrode 270 is disposed on a second substrate 210 of theupper panel 200. The common electrode 270 may include a transparentconductive material such as ITO and IZO, for example. A constant voltagemay be applied to the common electrode 270, and an electric field may begenerated between the pixel electrode 191 and the common electrode 270.

First cutouts 271 a and 271 b are defined in the common electrode 270.The first cutouts 271 a and 271 b of the common electrode 270 includethe first cutout 271 a disposed at a position corresponding to the firstsub-pixel electrode 191 h and the first cutout 271 b disposed at aposition corresponding to the second sub-pixel electrode 191 l.

The first cutouts 271 a and 271 b of the common electrode 270 may have across shape when viewed from a top view. End portions of the firstcutouts 271 a and 271 b are further protruded from edges of the firstsub-pixel electrode 191 h and the second sub-pixel electrode 191 l,respectively. As described above, in such an embodiment, where an edgeof a cutout of the common electrode 270 is further protruded from anedge of the pixel electrode 191, a fringe field may be further stablyinfluence an edge of a pixel region and thereby, alignment of liquidcrystal molecules is effectively adjusted in a predetermined directioneven at the edge of the pixel region.

The width of each of the first cutouts 271 a and 271 b of the commonelectrode 270 may be less than or equal to about three times the heightof the liquid crystal layer 3, that is, a cell gap. Herein, a width of acutout may be defined as a length of the cutout in a directionsubstantially perpendicular to an extending direction of the cutout.

A second alignment layer 21 is disposed on the common electrode 270. Thesecond alignment layer 21 may be a vertical alignment layer, and may bean alignment layer photo-aligned using a photo-polymerization material.

A polarizer (not shown) may be provided on an outer surface of each ofthe lower panel 100 and the upper panel 200. Polarization axes of twopolarizers on the outer surface of the lower panel 100 and the upperpanel 200 are substantially orthogonal to each other and a polarizationaxis of one of the two polarizers may be substantially parallel to anextending direction of the gate line 121. In an exemplary embodiment,where the display device is a reflection type display device, one of thetwo polarizers may be omitted.

The liquid crystal layer 3 has a negative dielectric anisotropy, andlongitudinal axes of liquid crystal molecules of the liquid crystallayer 3 are aligned to be substantially vertical with respect to thesurface of two display panels, that is, the lower panel 100 and theupper panel 200 in a state in which an electric field is not generatedtherebetween. Accordingly, in a state in which the electric field is notgenerated, incident light is blocked by the two polarizers havingpolarization axes substantially perpendicular to each other.

The first sub-pixel electrode 191 h and the second sub-pixel electrode191 l, to which data voltage is applied, generate the electric fieldtogether with the common electrode 270 and thereby, determine adirection of each liquid crystal molecules 310 of the liquid crystallayer 3 positioned between two electrodes, that is, the pixel electrode191 and the common electrode 270. Luminance of light passing through theliquid crystal layer 3 varies based on the determined direction ofliquid crystal molecules 310.

The first sub-pixel electrode 191 h and the common electrode 270 formthe first liquid crystal capacitor (Clch) together with the liquidcrystal layer 3 disposed therebetween. The second sub-pixel electrode191 l and the common electrode 270 form the second liquid crystalcapacitor (Clcl) together with the liquid crystal layer 3 disposedtherebetween. Accordingly, the first and second thin film transistors(Qh and Ql) maintain the applied voltage even after the first and secondthin film transistors (Qh and Ql) are turned off.

The first and second sub-pixel electrodes 191 h and 191 l overlap thestorage electrode line 131 or the storage electrode 133 to thereby formthe first and second storage capacitors (Csth and Cstl), respectively.The first and second storage capacitors (Csth and Cstl) reinforcevoltage storage capacity of the first and second liquid crystalcapacitors (Clch and Clcl), respectively.

Wide end portions of the protruding portion 134 and a wide end portion177 c of the third source electrode 173 c overlap each other based onthe gate insulating layer 140 to thereby form the decompressioncapacitor (Cstd).

As described above, in an exemplary embodiment, the first sub-pixelelectrode 191 h and the second sub-pixel electrode 191 l, to which thedata voltage is applied, generate the electric field together with thecommon electrode 270. Accordingly, in a state in which the electricfield is absent, the liquid crystal molecules 310 of the liquid crystallayer 3 aligned to be substantially vertical with respect to the surfaceof two electrodes, that is, the pixel electrode 191 and the commonelectrode 270 inclined in a direction substantially horizontal to thesurface of two electrodes, that is, the pixel electrode 191 and thecommon electrode 270, and luminance of light passing through the liquidcrystal layer 3 varies based on an inclination degree of liquid crystalmolecules 310.

The liquid crystal layer 3 includes the liquid crystal molecules 310having a negative dielectric anisotropy and a polymer. The liquidcrystal molecules 310 are aligned in a predetermined direction such thata longitudinal axis thereof has a pretilt angle by the polymer to besubstantially parallel to a direction that faces a middle portion of thecross-shaped first cutouts 271 a and 271 b of the common electrode 270from four portions at which edges of the sub-pixel electrodes 191 h and191 l extending in different directions meet, by the first cutouts 271 aand 271 b of the common electrode 270 and the edges of the first andsecond sub-pixel electrodes 191 h and 191 l, and to be substantiallyvertical to the surface of the first substrate 110. Accordingly, each ofthe first and second sub-pixel electrodes 191 h and 191 l has foursub-regions in which pretilt directions of liquid crystal molecules 310are different from each other.

Hereinafter, a unit region of a field generating electrode of anexemplary embodiment of an LCD, according to the invention, will bedescribed with reference to FIG. 4.

FIG. 4 is a top plan view illustrating a unit region of a fieldgenerating electrode of an exemplary embodiment of an LCD, according tothe invention.

As illustrated in FIG. 4, the unit region of the field generatingelectrode includes the pixel electrode 191 disposed to face a firstcutout 271 in the common electrode 270, and a second cutout 91 in thepixel electrode 191 disposed to surround the first cutout 271 in thecommon electrode 270. When viewed from a top view, the unit regiondefined by the first cutout 271 in the common electrode 270 and the edgeof the pixel electrode 191 may be divided in a plurality of sub-regions(Da, Db, Dc and Dd). The plurality of sub-regions may be disposedsymmetrical to each other with respect to the first cutout 271 in thecommon electrode 270.

The second cutout 91 in the pixel electrode 191 has a substantiallyrectangular ring shape along the edge of the pixel electrode 191, and isdisconnected around a portion corresponding to an end portion of thefirst cutout 271 in the common electrode 270. As described above, aportion on the pixel electrode 191 where the second cutout 91 in thepixel electrode 191 is disconnected may be a connecting portion of thepixel electrode 191. A width of the connecting portion of the pixelelectrode 191 is greater than a width of the first cutout 271 in thecommon electrode 270 corresponding thereto.

An opening 187 is defined in the second passivation layer 180 qpositioned below the pixel electrode 191, and accordingly, the pixelelectrode 191 has a step structure having a height differencecorresponding to the thickness of the second passivation layer 180 q.The boundary line of the step structure and the outline of the opening187 may have a rhombus shape, and the first cutout 271 in the commonelectrode 270 is disposed to overlap two diagonals in the rhombus shape.

A liquid crystal controlling power of a portion towards four vertices ofthe pixel electrode 191 from a central portion of the first cutout 271in the common electrode 270 may become relatively weak compared to otherportions. In an exemplary embodiment of an LCD according to theinvention, the portion having the relatively weak liquid crystalcontrolling power is reinforced by providing the step on the pixelelectrode 191 and by additionally generating a fringe field. In such anembodiment, a texture controlling power is substantially improved byadditionally generating the fringe field.

In such an embodiment of the LCD, a cross-shaped cutout is formed on acommon electrode, but not being limited thereto. In an alternativeexemplary embodiment, the cutout may be defined or formed on at leastone of a pixel electrode, that is, a field generating electrode, and thecommon electrode. In one exemplary embodiment, for example, thecross-shaped cutout may be formed on the pixel electrode. In onealternative exemplary embodiment, for example, the cross-shaped cutoutmay be formed on all of the pixel electrode and the common electrode.

Hereinafter, an exemplary embodiment of a method of initially aligningthe liquid crystal molecules 310 to have a pretilt angle will bedescribed with reference to FIG. 5.

FIG. 5 is a view illustrating an exemplary embodiment of a process ofenabling liquid crystal molecules to have a pretilt angle using aprepolymer polymerized by light such as ultraviolet rays.

In such an embodiment, a prepolymer 330 such as monomer to be hardenedby polymerization by light such as ultraviolet rays is injected betweentwo display panels, that is, the lower panel 100 and the upper panel200, together with a liquid crystal material. The prepolymer 330 may bereactive mesogen that performs the polymerization by light such asultraviolet rays.

Next, an electric field is generated on the liquid crystal layer 3disposed between two field generating electrodes by applying a datavoltage to the pixel electrode 191 and applying a common voltage to thecommon electrode 270. Next, in response to the electric field, theliquid crystal molecules 310 of the liquid crystal layer 3 are tilted tobe substantially parallel to a direction towards a middle portion of thefirst cutout 271 in the common electrode 270 in a cross shape from fourvertices of the pixel electrode 191 by a fringe field generated by thefirst cutout 271 in the common electrode 270 and the second cutout 91 inthe pixel electrode 191. In a unit region, the liquid crystal molecules310 are tilted in a total of four directions. In such an embodiment, theliquid crystal molecules 310 positioned on four sub-regions that definea unit region are aligned to have different pretilt angles.

In an exemplary embodiment, as described above, the prepolymer 330 ispositioned between the liquid crystal molecules 310, but the inventionis not limited thereto. In an alternative exemplary embodiment, theprepolymer 330 may also be included in the first and second alignmentlayers 11 and 21 as well as the liquid crystal layer 3. In such anembodiment, when forming the first alignment layer 11 and the secondalignment layer 21, the prepolymer 330 may be provided on each of thefirst substrate 110 and the second substrate 210 together with analignment material. The prepolymer 330 may be reactive mesogen thatperforms the polymerization by light such as ultraviolet rays.

Here, the first and second alignment layers 11 and 21 positioned on foursub-regions that define a unit region have different pretilt angles.

Next, an alternative exemplary embodiment of an LCD, according to theinvention, will be described with reference to FIG. 6.

FIG. 6 is a cross-sectional view illustrating a pixel of an alternativeexemplary embodiment of an LCD, according to the invention.

The LCD shown in FIG. 6 is substantially the same as the LCD shown inFIGS. 1 to 5 except for a groove portion of the color filter 230. Thesame or like elements shown in FIG. 6 have been labeled with the samereference characters as used above to describe the exemplary embodimentsof the LCD shown in FIGS. 1 to 5, and any repetitive detaileddescription thereof will hereinafter be omitted or simplified.

In the lower panel 100 of an alternative exemplary embodiment of theLCD, as shown in FIG. 6, the first passivation layer 180 p, the colorfilter 230, the light blocking member 220 and the second passivationlayer 180 q are sequentially disposed or stacked on the first substrate110.

The openings 187 a and 187 b in the rhombus shape are defined on thesecond passivation layer 180 q, and the color filter 230 may have agroove portion 231 in the rhombus shape in a portion thereof positionedbelow the openings 187 a and 187 b in the second passivation layer 180q. The outline of the groove portion 231 matches the outline of theopenings 187 a and 187 b in the second passivation layer 180 q.

The pixel electrode 191 is disposed on the second passivation layer 180q, the openings 187 a and 187 b and the groove portion 231, such thatthe pixel electrode 191 has a step structure at an outline of the grooveportion 231. Accordingly, the boundary line of the step structurematches the outline of the groove portion 231.

The outline of the groove portion 231 has substantially the same shapeas the boundary line of the step structure, and a vertex of the rhombusshape defining the outline of the groove portion 231 may be chamfered.

A side surface of the groove portion 231 may have an angle in a range ofabout 35 degrees to about 65 degrees with respect to a bottom surface ofthe groove portion 231.

A sum of the thickness of the second passivation layer 180 q and thedepth of the groove portion 231 may be in a range of about 500 Å toabout 2,200 Å.

In the upper panel 200, the common electrode 270 is disposed on thesecond substrate 210. The first cutout 271 in the common electrode 270is disposed to overlap two diagonals in the rhombus shape of the grooveportion 231.

In an exemplary embodiment, as described above, a groove portion isdefined in a color filter, but the invention is not limited thereto. Inan alternative exemplary embodiment, the groove portion may be providedin another organic material layer, for example, an organic insulatinglayer or an overcoat.

Hereinafter, texture controlling power and transmittance in an exemplaryembodiment of an LCD according to the invention will be described withreference to FIGS. 7 through 9.

FIG. 7 is a graph illustrating an stain visibility level based on aheight of a step structure of a pixel electrode in an exemplaryembodiment of an LCD according to the invention, FIG. 8 is a graphillustrating an stain visibility level based on a tapered angle of asecond passivation layer in an exemplary embodiment of an LCD accordingto the invention, and FIG. 9 is a graph illustrating a transmittancebased on a height of a step structure of a pixel electrode in anexemplary embodiment of an LCD according to the invention.

In FIG. 7, a horizontal axis denotes a height of the step structure ofthe pixel electrode. In an exemplary embodiment, the step structure ofthe pixel electrode may be provided by an opening of the secondpassivation layer and may also be provided by the color filter. In FIG.7, from the leftmost bar of the horizontal axis, bars sequentiallyindicate a reference case in which the step structure of the pixelelectrode is absent, an embodiment in which only the opening of thesecond passivation layer is formed and the thickness of the secondpassivation layer is about 700 Å, an embodiment in which the thicknessof the second passivation layer is about 1000 Å, an embodiment in whichthe opening of the second passivation layer and the groove portion ofthe color filter are formed and the thickness of the second passivationlayer is about 700 Å, and the depth of the groove portion is about 500Å, an embodiment in which the thickness of the second passivation layeris about 700 Å and the depth of the groove portion is about 1000 Å, andan embodiment in which the thickness of the second passivation layer is700 Å and the depth of the groove portion is 1500 Å. The vertical axisof the graph shown in FIG. 7 denotes the stain visibility level, and thestain visibility level decreases as the texture controlling powerincreases.

Compared to the reference case in which the step structure of the pixelelectrode is absent, the stain visibility level decreases in anembodiment in which the step structure of the pixel electrode isprovided. For example, in an embodiment in which the thickness of thesecond passivation layer is about 700 Å and the depth of the grooveportion is about 500 Å and thereby, the step structure of the pixelelectrode corresponding to a total of about 1200 Å is defined, the stainvisibility level is improved by about 45% compared to the reference casein which the step structure of the pixel electrode is absent.

In FIG. 8, a horizontal axis denotes a tapered angle of the secondpassivation layer at a portion in which the opening is defined or atapered angle of the color filter at a portion in which the grooveportion is defined. A vertical axis denotes the stain visibility level.

As shown in FIG. 8, the stain visibility level minutely decreases as thetapered angle increases. However, when the tapered angle is less thanabout 35 degrees, the liquid crystal controlling power may decrease.When the tapered angle becomes to be greater than about 65 degrees,light leakage occurs in a black state and thus, a contrast ratiodecreases. Accordingly, in an exemplary embodiment, the tapered anglemay be in a range of about 35 degrees to about 65 degrees.

In FIG. 9, a horizontal axis denotes a height of the step structure ofthe pixel electrode, as in the graph shown in FIG. 7, and a verticalaxis denotes the transmittance.

As shown in FIG. 9, compared to a reference case in which the stepstructure of the pixel electrode is absent, the transmittance isimproved in an embodiment in which the step structure of the pixelelectrode is provided.

Next, another alternative exemplary embodiment of an LCD according tothe invention will be described with reference to FIG. 10.

FIG. 10 is a top plan view illustrating a unit region of a fieldgenerating electrode of an LCD according to an exemplary embodiment ofthe invention.

The LCD shown in FIG. 10 is substantially the same as the LCD shown inFIGS. 1 to 5 except for the field generating electrode. The same or likeelements shown in FIG. 6 have been labeled with the same referencecharacters as used above to describe the exemplary embodiments of theLCD shown in FIGS. 1 to 5, and any repetitive detailed descriptionthereof will hereinafter be omitted or simplified.

As illustrated in FIG. 10, the unit region of the field generatingelectrode may include the pixel electrode 191 disposed to face the firstcutout 271 in the common electrode 270 and the second cutout 91 in thepixel electrode 191 disposed to surround the first cutout 271 in thecommon electrode 270.

In an exemplary embodiment, as described above, the horizontal lengthand the vertical length of the unit region of the field generatingelectrode may be equal to or symmetrical to each other as shown in FIG.4. In an alternative exemplary embodiment, as shown in FIG. 10, thehorizontal length and the vertical length may be different from orasymmetrical to each other.

When the horizontal length and the vertical length are asymmetrical toeach other, the liquid crystal controlling power may decrease andtexture may occur. In an exemplary embodiment, where the horizontallength and the vertical length are asymmetrical to each other, thetexture controlling power is improved by providing the step structure onthe pixel electrode 191 and thereby improving the liquid crystalcontrolling power.

Next, another alternative exemplary embodiment of an LCD according tothe invention will be described with reference to FIGS. 11 and 12.

FIG. 11 and FIG. 12 are top plan views illustrating a unit region of afield generating electrode of alternative exemplary embodiments of anLCD according to the invention.

The LCD shown in FIG. 11 or 12 is substantially the same as the LCDshown in FIGS. 1 to 5 except for an angle between the boundary line ofthe step structure of the pixel electrode and the first cutout in thecommon electrode. The same or like elements shown in FIG. 6 have beenlabeled with the same reference characters as used above to describe theexemplary embodiments of the LCD shown in FIGS. 1 to 5, and anyrepetitive detailed description thereof will hereinafter be omitted orsimplified.

A first cutout 271 in a common electrode is provided in a cross shapeand thus, includes a horizontal cutout and a vertical cutout.

In an alternative exemplary embodiment, as shown in FIG. 11, an anglebetween a horizontal cutout of the first cutout 271 in the commonelectrode and a boundary line of a step structure of a pixel electrode191 is about 45 degrees or more, for example, about 50 degrees. In anexemplary embodiment in which the step structure of the pixel electrode191 is provided by an opening 187 of a second passivation layer, anangle between an outline of the opening 187 of the second passivationlayer and the horizontal cutout of the first cutout 271 in the commonelectrode is about 50 degrees. In an alternative exemplary embodiment,in which the step structure of the pixel electrode 191 is provided bythe opening 187 of the second passivation layer and a groove portion ofa color filter, an angle between the outline of the groove portion andthe horizontal cutout of the first cutout 271 in the common electrode isabout 50 degrees.

As described above, in an exemplary embodiment in which the anglebetween the horizontal cutout of the first cutout 271 in the commonelectrode and the boundary line of the step structure of the pixelelectrode 191 is 45 degrees or more, horizontal visibility may beimproved by decreasing an azimuth of an initial pretilt of liquidcrystal molecules.

In another alternative exemplary embodiment, as shown in FIG. 12, anangle between the horizontal cutout of the first cutout 271 in thecommon electrode and the boundary line of the step structure of thepixel electrode 191 is 45 degrees or less, for example, about 40degrees. In an exemplary embodiment in which the step structure of thepixel electrode 191 is provided by the opening 187 of the secondpassivation layer, an angle between the outline of the opening 187 ofthe second passivation layer and the horizontal cutout of the firstcutout 271 in the common electrode is about 40 degrees. In analternative exemplary embodiment, in which the step structure of thepixel electrode 191 is provided by the opening 187 of the secondpassivation layer and the groove portion of the color filter, an anglebetween the outline of the groove portion and the horizontal cutout ofthe first cutout 271 in the common electrode is about 40 degrees.

As described above, in such an embodiment in which the angle between thehorizontal cutout of the first cutout 271 in the common electrode andthe boundary line of the step structure of the pixel electrode 191 is 45degrees or less, vertical visibility may be improved by increasing anazimuth of an initial pretilt of liquid crystal molecules.

As described above, in an exemplary embodiment of an LCD, an anglebetween the first cutout 271 in the common electrode and the boundaryline of the step structure of the pixel electrode 191 may be adjustedwithin the range of about 40 degrees to about 50 degrees to improve thehorizontal visibility or the vertical visibility of the LCD.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A liquid crystal display, comprising: a firstsubstrate; a second substrate disposed opposite to the first substrate;a pixel electrode disposed on the first substrate; a common electrodedisposed on the second substrate; and a liquid crystal layer disposedbetween the first substrate and the second substrate, wherein a firstcutout having a cross shape is defined in the common electrode, a secondcutout is defined in the pixel electrode to be adjacent to and along anedge of the pixel electrode, the pixel electrode has a step structure,and a boundary line of the step structure has a rhombus shape.
 2. Theliquid crystal display of claim 1, wherein the first cutout overlaps twodiagonal lines in the rhombus shape of the boundary line of the stepstructure.
 3. The liquid crystal display of claim 2, wherein a vertex ofthe rhombus shape of the boundary line of the step structure ischamfered.
 4. The liquid crystal display of claim 2, wherein a sidesurface of the pixel electrode at the boundary line of the stepstructure forms an angle in a range of about 35 degrees to about 65degrees with the first substrate.
 5. The liquid crystal display of claim2, wherein the step structure has a height difference in a range ofabout 500 angstroms to about 2,200 angstroms.
 6. The liquid crystaldisplay of claim 2, wherein an angle between the boundary line of thestep structure and the first cutout is in a range of about 40 degrees toabout 50 degrees.
 7. The liquid crystal display of claim 1, furthercomprising: a passivation layer disposed below the pixel electrode,wherein an opening in the rhombus shape is defined in the passivationlayer.
 8. The liquid crystal display of claim 7, wherein the boundaryline of the step structure matches an outline of the opening in thepassivation layer.
 9. The liquid crystal display of claim 7, wherein thefirst cutout overlaps two diagonal lines in the rhombus shape of theopening in the passivation layer.
 10. The liquid crystal display ofclaim 9, wherein a vertex of the rhombus shape of the opening in thepassivation layer is chamfered.
 11. The liquid crystal display of claim9, wherein a side surface of the passivation layer which defines theopening has a tapered angle in a range of about 35 degrees to about 65degrees.
 12. The liquid crystal display of claim 9, wherein a thicknessof the passivation layer is in a range of about 500 angstroms to about2,200 angstroms.
 13. The liquid crystal display of claim 9, wherein anangle between an outline of the opening in the passivation layer and thefirst cutout is in a range of about 40 degrees to about 50 degrees. 14.The liquid crystal display of claim 7, further comprising: an organicmaterial layer disposed below the passivation layer; and the organicmaterial layer comprises a groove portion in the rhombus shape.
 15. Theliquid crystal display of claim 14, wherein the organic material layercomprises at least one of a color filter, an organic insulating layerand an overcoat.
 16. The liquid crystal display of claim 14, wherein theboundary line of the step structure matches an outline of the grooveportion of the organic material layer.
 17. The liquid crystal display ofclaim 14, wherein the first cutout overlaps two diagonal lines in therhombus shape of the groove portion.
 18. The liquid crystal display ofclaim 17, wherein a side surface of the groove portion forms an angle ina range of about 35 degrees to about 65 degrees with respect to a bottomsurface of the organic material layer.
 19. The liquid crystal display ofclaim 1, further comprising: a first alignment layer disposed on thefirst substrate and the pixel electrode; and a second alignment layerdisposed on the second substrate and the common electrode, wherein thefirst alignment layer and the second alignment layer are verticalalignment layers, the liquid crystal layer comprises liquid crystalmolecules and reactive mesogen, and the liquid crystal molecules arealigned to have a pretilt angle.
 20. The liquid crystal display of claim1, further comprising: a first alignment layer disposed on the firstsubstrate and the pixel electrode; and a second alignment layer disposedon the second substrate and the common electrode, wherein the firstalignment layer and the second alignment layer comprises an alignmentmaterial and reactive mesogen, and the first alignment layer and thesecond alignment layer align liquid crystal molecules in the liquidcrystal layer to have a pretilt angle.